A panoramic image means an image obtained by previously setting an image layer trace to be obtained, photographing the images along the trace, and then, linking the obtained images. Generally, as illustrated in FIG. 1, an apparatus for obtaining a panoramic image obtains the panoramic image by reconstructing images obtained by irradiating radiation such as X-rays, or the like, to image layer traces where a region of interest 2 of a subject is located.
An apparatus for obtaining oral a panoramic image according to the related art is focused to a subject, an arch shape, when it rotates. Therefore, the apparatus for obtaining an oral panoramic image essentially scans a cervical spine 3 and brings out unbalance of contrast since X-rays are reduced at the time of obtaining images of anterior teeth due to the cervical spine.
When diagnosing a patient's state with the image having the non-uniform contrast, it is difficult to accurately determine the state of the arch that appears being overlapped with the cervical spine 3 portion darker than a peripheral portion thereof due to a cervical effect.
A wrong operation may be performed on a patient when a misdiagnosis is made about a patient's arch state due to the above problems, which is highly likely to cause medical accidents.